Sarcoidosis (sar"koi-do'sis) involves inflammation that produces tiny lumps of cells in various organs in your body. The lumps are called granulomas (gran"u-lo'mahs) because they look like grains of sugar or sand. They are very small and can be seen only with a microscope. These tiny granulomas can grow and clump together, making many large and small groups of lumps. If many granulomas form in an organ, they can affect how the organ works. This can cause symptoms of sarcoidosis.